Cryptology ePrint Archive: Report 2003/227

Attacks on a Secure Group Communication Scheme With Hierarchical Access Control

Willi Geiselmann and Rainer Steinwandt

Abstract: At ICICS 2001, Zou, Ramamurthy, and Magliveras proposed CRTHACS, a chinese remainder theorem based scheme for secure group communication with hierarchical access control. The scheme is designed in such a way that the underlying hierarchy remains hidden from the participating parties/users.
This contribution describes several practical attacks on CRTHACS which can reveal significant parts of the hierarchy.